With stringent emissions requirements on automobiles, precise control of the air/fuel ratio delivery to the vehicle engine, which affects vehicle emissions, is required. To obtain the required precise control of air/fuel ratio delivered to the engine, air flow to the engine is typically measured and the fuel is scheduled based on the amount of air flowing into the engine. The resulting air/fuel ratio into the engine is optimized to thereby provide cleaner engine exhaust.
Typically, mass air flow into the engine is measured with a mass air flow sensor comprising an assembly of discrete components. As high performance of the mass air flow sensors is desired, ideal requirements for mass air flow sensors include fast response, environmental insensitivity, operation over a large air flow range and the ability to detect bi-directional flow. What is desired is a mass air flow sensor that obtains all of these advantages without the required cost of assembling discrete components.